Some communications equipment can operate in more than one power management mode. The power management mode determines the power consumption, and is selected to reduce power consumption. As mentioned in ATIS-0600015.02.2009, for transport equipment, the energy efficiency can be determined from the power consumption according to:Telecommunications Energy Efficiency Ratio(TEER)=data throughput/power consumption
The power consumption of communications equipment can be tested at different traffic loads, e.g. three different traffic loads. For example, the power consumption is separately measured when the equipment is handling a traffic load of 100%, 50% and 0% of a maximum throughput. An average of different levels can be calculated.
This measure of energy efficiency considers only particular discrete traffic loads, e.g. only three different traffic loads. Thus, the testing does not fully replicate conditions which closely resemble typical traffic flows.